1. Technical Field
The present invention relates to a method for manufacturing an organic EL device, and to an organic EL device and an electronic apparatus.
2. Related Art
Organic EL (electroluminescence) devices have a structure having a light-emitting function layer including a luminescent layer between an anode and a cathode. The light-emitting function layer may be a multilayer composite including a hole transport layer, a luminescent layer, and an electron transport layer in that order from the anode side. By applying a voltage between the anode and the cathode, holes and electrons are injected respectively from the electron transport layer and the hole transport layer to the luminescent layer, and light is emitted when the electrons and the holes are recombined to each other.
The organic EL device can be manufactured by a coating method, which allows easy patterning over a large area and efficient use of materials. However, the blue luminescent layer (B) formed by coating has not yet reached such level as can be put to practical use, while the red luminescent layer (R) and the green luminescent layer (G) are at a practical level in light emitting characteristics, such as lifetime. On the other hand, blue luminescent layers (B) formed by vapor deposition are reaching a practical level.
For example, JP-A-2007-73532, JP-A-2003-332055 and JP-A-10-153967 disclose methods in which the red luminescent layer (R) and the green luminescent layer (G) are formed by coating, while the blue luminescent layer (B) is formed over the entire surface overlying the red luminescent layer (R) and the green luminescent layer (G) by vapor deposition.
Unfortunately, charges are not smoothly transferred between macromolecular materials used for coating and low-molecular-weight materials used for vapor deposition. In other words, electrons are not easily injected to the luminescent layer that is to be excited for emitting light. Consequently, the luminous efficiency can be degraded or the lifetime of the luminescent layer can be reduced.